Although not a widespread practice, it is known in the stained-glass art to employ in windows, panels and similar works various types of rocks or stones which contribute to the beauty and esthetics of the completed art-work.
Certain stones and rocks, however, have been excluded from use in stained-glass applications because they lack sufficient strength and structural integrity to enable them to be worked thin enough to permit the passage of light therethrough. For example, many of the softer rocks or stones, such as alabaster and soapstone, can not be effectively employed because they will crumble or break before they can be worked as by grinding or cutting to a desired degree of thinness. Many hard rocks are also unusable for stained-glass applications because they are brittle or have fracture lines.